High-gain and high-speed amplifiers are vital in analog circuits and are used in a very wide range of applications. The increasing tendency towards low-voltage designs, especially as many devices and integrated circuits are made to smaller dimensions, causes significant problems in amplifier design.
A particular problem is that as the power supply voltage is scaled down in the design, the threshold voltage does not necessarily scale down in the same way. For an operational amplifier in such a situation conventional vertical gain enhancement techniques (cascoding) are no longer suitable for low-voltage applications and instead horizontal gain enhancement techniques (cascading) must be used. However with cascaded amplifiers the stability of the amplifier and its bandwidth are both limited by existing frequency compensation techniques.